Nothing substitutes for lived experience. To do accessibility and inclusion right, you have to:
1) Do the research
2) Do the research with the right people.
By all means, talk to caregivers, interpreters, and family members. But their perspectives may differ from the perspectives of the people with the actual disabilities. Figure out who your audience is, and serve them. If you think your audience doesn’t include people with disabilities, it does, you just haven’t realized that yet.
Alt text: if you want to find out what your disabled potential customers need, talk to THEM, not their friends, caregivers or family members.